chargé d'affaires

Definitions

from Wiktionary, Creative Commons Attribution/Share-Alike License

n. A diplomat, ranking below an ambassador, who heads a diplomatic mission when no ambassador is present, either temporarily (in the interim between the departure of one ambassador and the accreditation of another) or for an extended time.

Etymologies

from Wiktionary, Creative Commons Attribution/Share-Alike License

Borrowing from French chargé d'affaires (literally "[one] charged with matters").